The present disclosure relates to a controller for an internal combustion engine.
A type of internal combustion engine has been known that is equipped with a variable valve actuation device that changes the valve timing of the intake valve by changing the phase of the intake camshaft with respect to the crankshaft.
The controller of such an internal combustion engine sets a target phase of the intake camshaft such that a required load (target load) calculated based on the engine operating state is achieved. For example, refer to Japanese Laid-Open Patent Publication No. 2013-142339.
The target phase may be set such that, when the engine operating state is a steady state, the target phase is set to a value that gives priority to fuel economy, and that, when the engine operating state is a transient state, the target phase is set to a value that gives priority to the output torque so as to quickly achieve the required load.
However, the actual output torque obtained when the target phase is set to a transient state phase varies depending on various factors (for example, calculation errors and aged deterioration of the components of the internal combustion engine). Thus, even when setting the target phase to a value that gives priority to the output torque during a transient state, the output torque may not increase so much and the fuel economy may deteriorate.